Assessing the timing of amniotomy after Foley balloon catheter removal in women with labor induction: The role of Bishop score: An observational study

Abstract

The timing of amniotomy after the Foley balloon catheter removal is crucial for successful labor induction. This study aimed to assess the effects of the Bishop score on the timing of amniotomy in patients undergoing labor induction after the Foley balloon catheter removal. This was a retrospective cohort study based on electronic medical records. We performed a Chester sampling in patients with singleton-term pregnancies who initially underwent cervical ripening using a Foley balloon catheter at the Obstetrical Department of Taixing People's Hospital from January 2023 to July 2023. A total of 889 patients were admitted to the study. After excluding 330 patients according to the exclusion criteria, 103 patients were included. Following the Foley balloon removal, an amniotomy with a Bishop score < 6 was defined as an amniotomy with an unfavorable Bishop score (n = 62), and an amniotomy with a Bishop score ≥ 6 was defined as an amniotomy with a favorable Bishop score (n = 41). The primary outcome was the incidence of cesarean delivery and the interval from induction to delivery. The secondary outcomes included the incidence of operative vaginal delivery, intrapartum hemorrhage, postpartum hemorrhage, infection, thrombosis, and neonatal outcomes. All statistical comparisons were analyzed by GraphPad Prism 9. All data were presented as the mean ± SD or percentage. Statistical analysis comparing both groups was performed using the t test, chi-square test, or Fisher exact test where appropriate. The baseline data, operative vaginal delivery rate, postpartum hemorrhage rate, infection rate, thrombosis rate, intrapartum and postpartum hemorrhage volume, and neonatal outcomes showed no significant differences between the 2 groups. However, the cesarean delivery rate, interval from induction to delivery, and hemoglobin postdelivery decline were significantly decreased in the favorable Bishop score group. Amniotomy with a favorable Bishop score after Foley balloon catheter removal is linked to lower cesarean delivery rates, shorter induction-to-delivery intervals, and less postdelivery hemoglobin decline without increasing adverse maternal or neonatal outcomes.

Figure 1.

Patients’ eligibility and enrollment information for the current study. Of the 889 patients admitted to our institution during the study period, 103 were included in the analysis. We excluded patients with elective cesarean section, preterm (<37 weeks), premature rupture of membrane, without Foley balloon catheter, or oxytocin.

Figure 2.

Comparison of intrapartum and postpartum hemorrhage volume, hemoglobin decline after delivery, infection markers, and thrombosis markers between the 2 groups. A showed changes in intrapartum hemorrhage volume, postpartum hemorrhage volume, and hemoglobin decline after delivery in both groups. B–D showed changes in infection and thrombosis markers including leukocyte, neutrophil, and thrombocyte before after delivery in 2 groups. FBS = amniotomy with favorable Bishop score, UBS = amniotomy with unfavorable Bishop score. *P < .05.